Positioning device including means for dividing intervals into preselected numbers of equal parts



May 1963 J. A. RAVE, JR 3,089,989

POSITIONING DEVICE INCLUDING MEANS FOR mvxnms INTERVALS INTO PRESELEJCTED NUMBERS OF EQUAL PARTS Filed Sept. 14, 1959 4 Sheets-Sheet 1 57 Fig- 2 IN V EN TOR.

J SEFH fl-RA VE, JR Fig.1 0

ATTORNEYS 3,089,989 NG MEANS FOR DIVIDING INTERVALS INTO PRESELECTED NUMBERS OF EQUAL PARTS Filed Sept. 14, 1959 May 14, 1963 J. A. RAVE, JR

POSITIONING DEVICE INCLUDI 4 Sheets-Sheet 2 501W 506%? 8a 1 C e L5 3 :gij

5 7 [A w l INVENTOR.

JOSEPH A. 5/; v5, JR

BY ATTORNEY s May 14, 1963 J. A. RAVE, JR

POSITIONING DEVICE INCLUDING MEANS FOR DIVIDING INTERVALS INTO PRESELECTED NUMBERS OF EQUAL PARTS Filed Sept. 14, 1959 4 Sheets-Sheet 3 ace- Z 4m b m 7 9 3 m EA E WM a L 9876F5432 0 8 54F32 0 F s 7 I l l l l I I l .l|||..l 0 i J m w. r MWQ 6H m m s 7 5 m 9876 43 I\ 3w 7% 6 9 MM n 1 8 $4 3 o r W0 M s F W W s 2 987 65492 0 PM ,o m 0 wW 4 4 1 6 MW 543 2 0 9876 L J. A. RAVE, JR

May 14, 1963 3,089,989 NG MEANS FOR DIVIDING INTERVALS POSITIONING DEVICE INCLUDI INTO PRESELEICTED NUMBERS 0F EQUAL PARTS Filed Sept. 14, 1959 4 Sheets-Sheet 4 l m M rm fflmmivwllr =|m w mw m wmm mw QW NWW W A MA -36 x Qhmm M MQ\\ Q\ VR y fiv OHHHHHHO O O H W m6 AWQ\ QQ\ \Q\ m 1 Qb\ x Q J J Y R. f tEQX Q. .wmw z I 2 n f7- m 1 .A w w "W W- GEQWK I h u T W M NM w m w wtw 4 956 5 A United States Patent 3,03%,989 PUSITIQNING DEVIUE INQLUDING MEAN F012. DKVEDENG INTERVAIS INTO PRESELE'CTED NUMBERS Gil EQUAL PARTS Joseph A. Rave, in, Cincinnati, Ohio, assignor to The Cincinnati Miiiiug Machine 630., (Iiucinnati, Ohio, a corporation of (this Filed Sept. 14, 1%), Ser. No. 839,861 12 Ciaims. (Cl. 318-23) The present invention relates to a proportional divider or, more particularly, to a device for dividing a linear function into any given number of equal parts and then supplying these parts one at a time, seriatirn, or it may be used to divide a dimension into any given number of parts and then supply the parts one at a time until the given dimension is redintegrated.

The device of the present invention utilizes a transformer to provide the required division of the linear function into a given number of equal parts. The system is therefore essentially an analog system and division is accomplished by applying a reference voltage across a predetermined number of turns of the transformer winding. The total number of turns across which the reference voltage is thus applied represents the whole number of the parts into which the function or dimension is to be divided. The equal parts are then derived electrically by connecting taps on the transformer winding to the output of the system in such a manner as to provide as many equal voltage increments as there are parts in the whole function.

To obtain a high degree of accuracy in the division of the whole into its parts, a high quality toroidal transformer having a winding divided into a plurality of sections each provided with a suitable number of equipotential taps may be utilized. Such transformers are known to be capable of producing accuracies of better than one part in 100,000 when used as ratio dividers in an autotransformer arrangement. In other words, the accuracy of voltage division obtainable from the taps of such a transformer is better than 001%. For a inch range of movement this represents an overall accuracy of better than .0002 of an inch which is adequate for most purposes. In a preferred embodiment of the invention, stepping switches are provided for changing the taps on the transformer to effect incremental, equal changes in the output voltage, each change representing a part of the whole function or dimension. Means are also provided to count the parts and to terminate the operation when the function has been redintegrated. The voltage steps produced by the system may be converted into equal steps of mechanical movement by a servomechanisrn designed to suit the requirements of the system.

Although the proportional divider hereinafter to be disclosed is susceptible of many diiferent uses, it will be hereinafter described in connect-ion with a machine for drilling holes in the index plates of dividing heads. The manufacture of such plates requires that each of the circles of a given plate be divided into a predetermined number of equal parts and that this division be performed with great accuracy. Also, the number of holes per circle varies considerably and involves both even and odd numbers of holes. For example, a standard index plate may require circles containing 24-2-5-28-30-34-37-38-39-4l-42- 43 holes on one side, and 46-47-49-51-53-54-57-58-59-62- 66 holes on the other side. A high number index plate on the other hand, may require circles ranging from to 199 or more holes. Heretofore, the drilling of the circles of holes required very precise masters and a large number of such masters were needed to permit the manufacture of all of the different index plates offered for sale. With the present invention, however, this requirement no Patented May 14, 1%63 longer exists and each plate can be made with any desired number of holes per circle quickly and eificiently.

Hence, it is an object of the present invention to provide a new type of proportional divider for dividing a linear function or dimension into any given number of equal parts.

Another object of the invention is to provide a device which is adapted to divide a linear function or dimension into any given number of equal parts and then to supply the parts one at a time until the function or dimension is redintegrated.

Another object of the invention is to provide a device for dividing a Whole into any given number of equal parts and then to supply the parts one at a time while counting the same and stopping the operation of the device after the whole has been redintegrated.

Another object of the invention is to provide a device for applying a constant voltage across a selected number of taps of a tapped toroidal transformer and then deriving from the taps of the transformer an output voltage which varies by equal increments from zero to the input voltage, the number of increments being equal to the number of taps selected.

Another object of the invention is to provide a system for dividing a dimension into any selected number of equal parts, the system including devices for applying a reference voltage across a selected number of taps of a tapped toroidal transformer, deriving from the transformer an output voltage which varies from zero to the input reference voltage by equal voltage increments corresponding to the selected number of equal parts, and anslating the equal voitage increments into corresponding increments of mechanical movement.

With these and other objects in view which will become apparent from the following description, the invention includes certain novel features of construction and combinations of parts, the essential elements of which are set forth in the appendant claims, and a preferred form or embodiment of which will hereinafter be described with reference to the drawings which accompany and form a part of this specification.

In the drawings:

FIG. 1 is a front elevation of a radial drill provided with a rotary worktable which may be indexed to different positions by the novel control equipment comprising the present invention.

FIG. 2 is a diagrarnatic view showing the dividing transformer and the servomechanism controlled thereby to effect positioning of the rotary table.

FIG. 3a is a wiring diagram of the switching circuit for translating the input information and applying it to the dividing transformer.

FIG. 3b is a wiring diagram of the circuits which operate the stepping switches in a counting sequence so as to derive a stairstep output voltage from the dividing transformer for controlling the servomechanism.

HQ. 4 is a diagrammatic vie-w showing a modified system for dividing a linear dimension into a selected number of equal parts.

PEG. 5 is a schematic view illustrating the type of work performed by the system shown in FIG. 4.

Similar reference characters designate similar or identical elements and portions throughout the specification with follows, and throughout the different views of the drawings.

In FIG. 1 is shown a radial drill 10 of conventional design havin a base 11, a column 12 and a rail 13 on which is slidably mounted a head 14. The head carries a spindle 15 which is rotated and fed into the work by power supplied from a main drive motor 16. The spindle has chucked therein a drill 17 which lies above a rotary table 13 supported on the base 11. The workpiece to be drilled, such as an index plate 19, is held in place on the table by a clamping screw 26. A locating pin 21 in the table engages in a hole in the plate 19 to properly position the plate on the table and to constrain it to move in unison with the table.

Rotation of the table is effected by a motor 25 which drives a bevel gear 26 meshing with a ring gear 27 secured to the table. The motor 25 is part of a servomechanism which will be further shown and described hereinafter.

It will be assumed for the purpose of this description of the invention that a circle of 375 equally spaced holes is to be formed in the plate 19 and that the drill 10 is correctly set up for the job. The equipment for indexing the rotary table 13 includes a control cabinet, not shown, containing three settable selector switches 18W, 28W and 38W (FIG. 3a). Each switch has a wiper settable to ten diiferent positions which may be considered as being numbered from to 9, and the selected number of holes, i.e., 375, is set up on the switches. The hundreds digit 3 is set up on the switch 18W, the tens digit 7 is set up on the switch 25W, and the units digit is set up on the switch 38W. The selector switches may, for the purpose of the present disclosure, be considered to be of the manually settable type, although they could just as readily be considered to be stepping switches which are automatically settable to the proper positions under the control of a tape or card reader. It will be noted from FIG. 3a that the ten studs of switch 18W are each connected by wires 28 to a corresponding stud in a bank 185a of a stepping switch 158 (FIG. 3b). This switch is a S-bank rotary telephone type switch of conventional design which is commercially available from suppliers of automatic telephone equipment. Each bank of the switch includes a rotary wiper blade which is moved, always in the same direction, from one stud to the next by a pawl and ratchet device. Upon energization of the switch solenoid, a pawl is moved by an armature to pick up the next tooth of a ratchet wheel moving with the wiper blades. This cocks a spring which, when the switch solenoid is deenergized, restores the pawl and, in so doing, advances each wiper blade to the next stud in the bank. The stepping switch also includes interrupter break contacts (designated 18) which open when the coil is energized and close when it is deenergized. The switch also includes off normal make contacts (designated ONM) which close when the wiper blades move out of home position.

The studs of selector switch 28W are connected by wires 29 to the corresponding studs of a bank ZSSa of a stepping switch 285, and the studs of switch 38W are connected by wires 3%? to the corresponding studs of a bank SSSa of a stepping switch 388. In addition, ire studs of switch 28W are connected by wires 31 to the corresponding studs of a second bank ISSb of switch 188, and the studs of switch 38W are connected by wires 32 to corresponding studs of banks i880 and 2855 of stepping switches 18S and 258. The stepping switches 188, 283 and 35S and relays lCR to 5CR, inclusive, and their associated contacts, comprise an automatic translation or switching circuit which will be described in greater detail hereinafter.

A source of energizing potential for the circuits shown in FTGS. 3a and 3b is provided by terminals 35 which may be connected to the main power lines or any other suitable source of energizing potential. The left hand terminal is shown connected to a conductor 36 which constitutes one energizing line for the circuits, while the right hand terminal is shown connected through a switch 38 to a conductor 37 which constitutes the other energizing line for the circuits.

With the switches 13W, 25W, and 38W set up as shown in PEG. 3a, the number represented by the setting of the switches will be transferred to the stepping switches 158, 28S and 358 when the switch 38 is closed to energize lines 36 and 37.

Upon energization of lines 36 and 37, stepping switches 183, 255 and SSS (FIG. 3b) will step around until the wipers and banks 188a, 255a and 358a (FIG. 3a) match the settings of the selector switches. Thus, when the wiper for the hundreds order stepping switch bank 1SSa reaches the 3 stud, relay lCR will be energized through the normally closed contacts 4CR-l thereby opening the normally closed contacts lCR in FIG. 3b. This will prevent any further stepping of the stepping switch 185 through the interrupter break, or 1B, contacts 1SS-2. Likewise, when the wiper for the tens order stepping switch bank 258:: reaches the 7 stud, relay ZCR will be energized through the normally closed contacts 4CR-3 thereby opening the normally closed contacts 20R (FIG. 3b). The circuit to the stepping switch 255 through the 13 contacts 2SS2 is thus broken and further stepping of the switch is prevented. A similar result occurs when the wiper for the units order stepping switch bank 3SSa reaches the 5 stud. At this time, relay 3CR will be energized through the normally closed contacts 4CR-5 and open the normally closed contacts 3CR (FIG. 3b). This will prevent further stepping of the switch 353 through the TB contacts 3SS2. The 3 stepping switches 1S3, 28S, and 338 are now set to positions corresponding to those occupied by selector switches 18W, 25W and 33W. Hence, the wipers of stepping switch banks 135d, 2380 and SSS]; (FIG. 2) will also be set at 375 as will also the wipers of banks 158e, ZSSd and 3880 (FIG. 3b). The wipers of banks lSSd, 2358c and 3881) as thus positioned will cause an AC. reference voltage in lines 39 and 4th, for example, 10 volts A.C., to be placed across a number of turns of the winding of a transformer 41 which is either equal to the selected number 375, or a multiple thereof, depending upon the number of turns per tap in the units section of the transformer. The transformer 41 is preferably an autotransformer of the toroidal type which, due to its negligible flux leakage, is readily capable of producing a ratio accuracy of better than one part in 100,000.

The winding shown herein is in three sections each having ten taps. The device of the present invention is not limited to a winding having the three sections, as shown, and more or fewer sections may be employed without departing from the principle of the invention. The number of turns between taps in each section is the same so that the voltages between taps in a given section are all equal. The ratio between the number of turns per tap in the three sections is chosen to correspond to the radix of the number system being employed. If the decimal system is used, the ratio is, of course, 10. In the binary system it would be 2, in the tertiary system, 3, and so on. In the present description of the invention, it will be assumed that the decimal system is employed. Hence, if it is assumed that there is one turn between each tap in the units order section 42 of the transformer, then there should be 10 turns between each tap in the tens order section 43, and turns between each tap in the hundreds order section 44. Hence, current entering the section 44 from the line 4i! will flow through 300 turns between the 0 and 3 taps. It will then pass through a jumper 45 connecting the wipers 87 and 88 of banks 1850? and 2580 and flow through '70 turns in section 43, i.e., from tap 7 to tap 0. Sections 42 and 43 are connected by a lead 46 so that current will enter the 0 tap of the units section 42 where it will pass through 5 turns and then return to the line 39 through the 5" tap and wiper 86. It will thus be seen that the current traverses 375 turns of the transformer winding. If two turns per tap were provided in the units order winding instead of one, then the tens order taps would be spaced 20 turns apart and the hundreds order taps 200 turns apart. In this case, the current would flow through 750 turns instead of 375 turns. In the case of an arrangement utilizing 3 turns per tap in the units order section, the number of turns per tap in the tens and hundreds order sections would be 30 and 300, and so on. In any event, the member of turns energized would necessarily be a multiple of 375, the term multiple being understood to mean the number selected, i.e., 375, multiplied by an integer, such as 1, 2, 3, etc.

The output from the auto-transformer 41 is derived from the wipers of stepping switch banks iSSa, SSSZJ, and 6851) whose studs are connected to the same transformer taps as the studs of banks llSSd, 258C and SS-Sb, respectively. The wipers of the banks dSSa, SSSb and 6881) all start from O and step upwardly during the dividing cycle. The wiper for bank 458a is connected to the input of a servoamplifier 50 through the secondary winding 51 of a toroidal transformer 52. This transformer has a primary winding 53 which is bifilar wound with the secondary winding in order to reduce the flux leakage to a point where a very nearly perfect 1 to 1 transformation ratio is maintained between the primary and secondary windings of the transformer. The effect of this transformer is to add the voltages derived from sections 42. and 43 to the voltage derived from the section 44, the ends of the primary winding 53 being connected to the sliders for the banks SSSb and 6SSb. The summed voltages are transmitted by a lead 54 to one input of the servoamplificr, the output of which is connected by leads 55 and 56 with a transducer 57. The latter unit may, for example, comprise an electrohydraulic valve which is connected by suitable hydraulic lines 58 and 59 with the hydraulic servomotor 25.

As previously indicated, the servomotor drives bevel gear 26 which meshes with the ring gear 27 secured to the rotary table 18 which carries the workpiece 19. Also meshing with the ring gear is a bevel gear at) which, as indicated by dotted line 61, is connected with the input shaft of a position analogue unit 62. This unit may take various forms and, in the present embodiment of the invention, has been shown as a linear tapped potentiometer 63, the wiper arm of which is drivingly connected with the gear 60 by the connection 61. The potentiometer may be either a single turn or a multiple turn type, it being assumed for the purposes of the present disclosure that it is a turn potentiometer, i.e., one in which the wiper turns through 3600- in moving from one end of the winding to the other. In this case, the gear 27 must have ten times the number of teeth of the gear 60 so that one turn of the table will result in ten turns of the potentiometer shaft.

The ends of the potentiometer winding are connected to the ends of a toroidal transformer winding 64 which is tapped at intermediate points to provide voltage ratios which correspond to those provided by the potentiometer taps. These taps are then connected together as shown in FIG. 2 to reduce error in the potentiometer caused by loading. The ends of the potentiometer winding and toroidal transformer winding are connected between the lines 39 and 44) so as to cause the reference voltage to be applied across the windings. The feedback voltage derived from the potentiometer wiper is a linear function of the rotation of the table and this voltage is applied to the second input of the servoamplifier by a lead 65. In the servoamplifier, the voltage output from the transformer 41 is compared with the voltage from the feedback unit 62. and the error voltage, if any, is amplified and causes the servomotor to run until the error is reduced to zero.

At the beginning of the dividing cycle, the wipers of stepping switches 4S8, SSS and 688 are in their 0 position and the output from the transformer 41 is zero. The servomotor 25 will rotate the table 18 until the wiper of the feedback potentiometer 63 is at the bottom end of the winding so that the feedback voltage is also zero. The index plate will therefore be located in the O position and the first hole in the plate is drilled in this position.

In order to advance the workpiece /375 of a revolution preparatory to drilling the second hole therein, an advance push button AS (FIG. 3b) is then depressed which energizes the stepping switch 65S through the normally closed contacts 6CR-1 and 4CR-8 and a conductor 78. When the push button is released, the stepping switch will be deenergized and the wiper in bank 6SSb stepped to the l stud. A voltage equal to of the reference voltage will now be applied to the input of the servoamplifier and the servomotor will run until the feedback voltage from the potentiometer 63 is also equal to V of the reference voltage. The table 13 will therefore be turned through a corresponding fraction of one revolution whereupon the drill may be operated to drill a hole in the second position. Each time the push button AS is depressed, the table will advance a corresponding amount until all of the 375 positions have been located and drilled.

It will be noted from inspection of FIG. 3b of the drawings that the stepping switches 68S, SSS and 4SS are arranged to operate in a counting sequence. That is, upon advance of one of the stepping switches from the 9 stud to the 0 stud, the next higher order stepping switch will be advanced one step. This function is performed by the banks 588a and 6SSa of stepping switches SSS and 688 in which the 0 to 8 studs are left unconnected whereas the 9 stud is connected to the next higher order stepping switch. Thus, the 9 stud for the stepping switch 6S8 is connected by conductors 71 and 72 to the stepping switch SSS. Hence, when the push button AS is depressed with the wiper on the 9 stud in the bank 635a, current will flow both to stepping switch 6S8 and also to stepping switch SSS and cause both to advance one step when the push button is released. Similarly, the 9 stud in bank SSSa is connected by conductors 73 and 74 with the stepping switch 4S5.

To return the stepping switches 68S and SSS to their 0 positions, each bank dSSa and SSSa is provided with one or more studs 77 and 78 beyond the 9 position which are connected to the line 36 through IB contacts 6SS2 and 5SS-2 so that the stepping switches will automatically advance to the 0 stud. Since the latter stud is not connected, the switch will stop in the 0 position ready for the next impulse.

The automatic advance feature just described can be used to cause the divider to skip over certain positions, should this be found desirable. For example, in drilling a circle of bolt holes, it might be desirable to skip every fifth hole. By connecting the 4 and 9 studs in the bank S-Sa to the stud 77, the stepping switch 6S5 will be caused to step from the 3 stud to the 5 stud without stopping on the 4 stud, and from the 8 stud to the 0 stud without stopping on the 9 stud. This same idea can be extended to higher orders to cause skipping of groups of 10 or holes at a time, or, by utilizing additional banks of contacts on the SSS and 48S stepping switches, and by connecting the wipers for these banks in series with a stud or studs in the lower order banks, individual holes such as the 26th, 87th, l23rd etc. could be skipped.

Referring now to the stepping switch banks shown at the bottom of FIG. 3!), it will be observed that the stepping switch banks 1386, 25501 and 3580 will have the wipers positioned on the 3, 7 and 5 studs respectively, and that these wipers will remain in such positions throughout the dividing cycle. The wipers of stepping switch banks dSSb, SSSc and dSSc, on the other hand, all start at 6 and step up during the cycle in a regular numerical progression as above described. As the cycle progresses, the wiper of bank 4S5!) will eventually reach the 3 stud of this bank, the wiper of bank 5SSc will thereafter come to the 7 stud of this bank, and finally, the wiper of bank dSSc will reach the 5 stud. At this time the cycle is completed and a circuit will be established through the coil of relay dCR to energize the relay.

a The normally closed contacts CR-l (FIG. 317) will then open and disable the push button AS so that no further stepping of the stepping switches can result from the operation of this push button.

To restore the circuit to its initial condition preparatory to the next dividing cycle, a reset push button RS (FIG. 3a) is depressed and held momentarily until the stepping switches 4S3, SSS, and SS have returned to their home positions. The return of the stepping switches is effected by a relay 70R which is energized by depression of the push button and thereupon closes its contacts 7CR-1 (FIG. 3b), 7CR-2 and 7CR-4. The contacts 7CR-1 when closed, establish a circuit to switch 4S8 through 1B contacts 4SS2 and ONM contacts 4SS-3. Hence, the switch will step automatically to home or position when the ONM contacts will open and stop further stepping of the switch. In a similar manner, contacts 7CR-2 will establish a circuit to switch 588 through 13 contacts 5SS2, conductor '76 and ONM contacts 5SS3 and cause homing of this switch. The contacts 7CR-4 will establish a circuit to switch 655 through IE contacts 6SS-Z and ONM contacts SS-S to cause homing of switch ass.

If the function is to be divided into a number of equal parts which is less than ten, it is desirable that the hundreds section 44 of the transformer be used to accomplish the division rather than the units section 42. This is for obvious reason that if the reference voltage were placed across say three taps of the unit section, the number of turns would be so few as to virtually short circuit the reference voltage source. For the same reason, when the number selected lies between 10 and 99, it is desirable to use the hundreds and tens sections 44 and 43, respectively, of the transformer rather than the tens and units sections 43 and 42, respectively.

To accomplish this result, a switching circuit such as the one shown in FIG. 3a is provided so that the highest significant digit of the number set upon the selector switches is always set into the hundreds stepping switch bank dSSd. Likewise, the next lower digit, if any, is always set into the tens stepping switch bank ZSSc. Suppose, for example, that the number selected was 75 instead of 375. The switch 18W would then be set to read 6 instead of 3 and the switches 28W and 35W would be set as shown in FIG. 3a. When the lines 36 and 37 are energized, relay 4CR will be energized through a conductor 8!) which is connected to the O stud on switch lS'W. Contacts 4CR1 will open to disconnect the wiper 81 and contacts iCR-2 will close to connect relay ICR with the wiper S2 for the bank S!) through tie normally closed contacts 5CR1. Since the studs or" bank 13511 are connected by wires 31 with the corresponding studs of switch W, relay lCR will be energized and stop stepping of switch 15s when tie wiper 82 reaches the 7 stud in bank lSSb. Energization of relay 4-CR will also open contacts dCR-S so as to disable the wiper of bank ZSSa. It will also close contacts 4CR-4 and connect relay ZCR with the wiper $3 for bank 258]). The studs of this bank are connected by wires 32. with corresponding studs of switch 38W. Hence, relay ZCR will be energized and stop stepping of switch 285 when the wiper 33 reaches the 5 stud. Energization of relay dCR also opens contacts dCR-S thereby disconnecting wiper 84 of bank 388a. At the same time it will open contacts i-CR-d (FIG. 3b) to prevent automatic stepping of switch 358. Since line St) is now energized, a line 85 connected thereto will also be energized. This line is connected through the ONM contacts 3SS-3 (FIG. 3b) with the stepping switch SSS through the 1B contacts 3SS-2. Hence, the stepping switch SSS will be homed thereby moving the wiper 86 of bank 3SSb (FIG. 1) to its 0 position. It will now be seen that the transformer sections 43 and 44- are utilized instead of sections 42 and 43 and that the 7 tap of section 44 will be selected by the wiper S7, and the tap 5 of section 43 will be selected by the wiper 88. Since switch SSS was homed, wiper 86 will be at 0. Hence, the reference voltage will be placed across 750 turns of the transformer rather than turns.

Since contacts iCR-Y (FIG. 3b) are now closed and contacts CR-8 are open, depression of push button AS will not energize line 7% but, instead, will energize lines 71 and 72 to energize stepping switch SSS instead of 653. Hence, each time the push button is depressed and re leased, the switch 588 Will advance one step and increase the voltage in the output of transformer 41 by V of the reference voltage. Transfer from stepping switch 588 to 45$ on each ten steps of switch SSS will occur as before to cause a progressive increase in the output voltage each time the push button is depressed and released until all 75 steps have been eifected.

The cycle will be terminated in the same manner as before, i.e., wipers in bank iSSe, 288d and 3880 will be positioned at 7, 5 and 0 respectively, so that when the wipers of banks 43811 and SSSc reach 75, coincidence will be established and relay 6GP. energized to terminate the cycle.

Assuming now that the number of parts selected was 5 instead of 75, selector switches 13W and 23W will be at 0 while switch 3SW wil be set at 5. Relay lCR will be energized as before and, in addition, a relay SCR will be energized through a line 99. Energization of relay EECR causes contacts 5CR-1 and 5CR-2 (FIG. 3a) to open and close, respectively, thereby connecting relay iCR to wiper 91 of bank 1880. At the same time, contacts SCR-3 will open to disconnect wiper 83 of bank QZSS-b contacts SCR-d will close to connect the wiper of bank 2555a with relay ZCR. Since the studs of bank iSSc are connected by wires 32. to the corresponding studs of switch 33W, when the wiper M reaches the 5 stud, relay lCR will be energized and prevent further stepping of switch ISS. The Wiper of bank ZSSa will stop at 0 since switch ZSW is set at 0 and the contacts ECR-d will cause relay ZCR to be energized and prevent further stepping of switch 288 when it reaches 0. Stepping switch 383 will be horned, as before, to its 0 position. Hence, the wipers of banks lSSd, 233C and 3SSb (FIG. 1) will stand at 5, O and 0 respectively so as to connect 500 turns of transformer 41 across the reference voltage provided by lines 39 and it When the push button AS is depressed, only stepping switch 4853 will respond since contacts 5CR5 (FIG. 3b) are closed and contacts SCR-fi and 4CR8 are open. Hence, switch 455 will be pulsed while switches SSS and 68S will remain idle. When switch 458 has moved five steps, the wiper of bank 4881) will complete the circuit to relay 6CR and terminate the cycle.

The proportional divider heretofore described can be used to provide equal linear displacements as well as equal rotary displacements. A system for accomplishing this type of division is shown in FIGS. 4 and 5 of the drawings. Suppose, for example, that a selected number of holes ltiti (HG. 5) including a first hole lllll and a last hole 1% are to be drilled equal distances apart in a workpiece 83. In this example, it is assumed that the maximum linear distance to be divided is inches and that the reference voltage used in the system is 10 volts AC. Therefore 10 volts equals the whole range of movement, or 106 inches. The distance to be divided into a selected number or equal parts may be any distance up to 100 inches with the arrangement shown and the group of holes may be located in any desired location along the length of the workpiece. For this purpose, the system is zeroed at a first datum point 194 and the distance from this point to the first hole 101 of the group.

the last hole 102 to a second datum point 105, which 9 represents the end of the maximum range of the system, is 24.375 inches.

As shown in FIG. 4 the workpiece ms is mounted on a slide or table 1% which is guided for rectilinear sliding movement by ways 1&7. The table is arranged to be driven by a pinion ltltl which meshes with a rack Hi9 fastened to the table. The pinion is driven by a servomotor 116 through gears ill and 112. The servomotor also drives a gear 113 which is arranged to rotate the wiper arm 114 of a tapped linear potentiometer M which is supplied with the 10 volts A.C. reference voltage by a pair of conductors 116 and 1117. The taps on the potentiometer are connected to corresponding taps on a toroidal transformer winding 113 in the same manner and for the same purpose as previously described in connection with the system shown in FIG. 2.

In the embodiment of the invention shown in FIGS. 4 and 5, the toroidal transformer 119 which is utilized to accomplish the proportional division may be identical with the previously described transformer if (FIG. 2). However, the transformer is supplied with only 6.1875 volts instead of the full reference voltage so as to reduce the distance to be divided from 100 inches to 61.875 inches. If the bottom end of potentiometer H5 is assumed to correspond to the first datum point M4, and the upper end to correspond to the second datum point N5, then the lower end of transformer if? must be supplied with 1.3750 volts in order to move the slide to the location for the first hole fill, and wiper 12% at the upper end of the transformer must be supplied with 7.5625 volts in order to locate the last hole 24.375 inches from the second datum point 105. These voltages may be supplied, for example, from toroidal transformers H5 and 126 each having 160,000 turns and tapped every turn to provide the necessary resolution of the reference voltage. A more convenient method would be to utilize the type of unit described in US. patent application Serial No. 620,145, filed November 2, 1956, by R. E. Spencer, R. A. Cail and F. C. Wolfendale for Converters for Converting Digital Information into Analogue Information. With the system therein disclosed, digital information taken from a tape or card reader can be converted into the analog voltages required by the present system as an input for the transformer 11) supplied via lines 127 and 128. Alternatively, any other convenient means for providing an alternating current voltage analogue of a dimensional quantity with the required accuracy might be used in place of the toroidal transformers 125 and 126 shown herein.

The output of the dividing transformer H9 is transmitted by a conductor 129 to the input of a servoamplifier 13ft where it is compared with a second input voltage obtained from the feedback unit through a conductor Hi. The difference between the two voltages is amplified and applied to a transducer 132 which controls the servomotor and causes it to run until the voltages are equal.

Having thus described the invention in connection with one possible form of a rotary dividing apparatus and also of a linear dividing apparatus, and having used certain specific terms and language in describing the particular apparatus disclosed, it is to be understood that the present description is illustrative rather than restrictive and that changes and modifications may be resorted to without departing from the spirit of the invention as defined by the claims which follow.

I claim:

1. In a device for dividing a linear function into a selected number of equal parts, the combination of a transformer having a winding with a plurality of equally spaced voltage taps thereon, switch means for selectively connectiong a reference voltage across a number of taps on the transformer winding equal to the number of parts in the linear function to be divided, a slider movable 'rom one tap to the next seriatim, and a servomechanism for translating the voltage increments derived from the individual taps by the slider into equal steps of mechanical movement, said steps being proportional to the magnitude of the voltage increments derived from the successive taps on the transformer, said servornechanism including a feedback unit, and means for driving the feedback unit in accordance with the mechanical movement produced by the servomechanism to provide a feedback voltage which is linearly related to the mechanical movement and which is equal to the reference voltage when the mechanical movement is equal to the whole of the linear function.

2. The device of claim 1 wherein said feedback unit is energized by said reference voltage.

3. In a device for dividing the movement of an element through a predetermined distance into any selected number of equal parts, the combination of a toroidal autotransformer having a winding with a plurality of equally spaced voltage taps thereon, switch means for selectively connecting a reference voltage across a number of taps on the transformer Winding equal to the number of parts selected, a slider movable from one tap to the next seriatim, and a servomechanism for moving said element through distances proportional to the voltages derived from the taps on the transformer by the slider, said servomechanism including a feedback unit energized by said reference voltage, means for driving the feedback unit in accordance with the movement of said element to provide a feedback voltage which is linearly related to the movement of the element and which is equal to the reference voltage when the element moves through said predetermined distance, and a servoamplifier for comparing the voltage derived from said taps with the feedback voltage and for amplifying the difference, if any between said voltages.

4. In a device for dividing a circle into any selected number of equal parts, the combination of a rotatable element, a transformer having a winding with a plurality of equally spaced voltage taps thereon, switch means for selectively connecting a reference voltage across a number of taps on the transformer winding equal to the number of parts selected, a slider movable from one tap to the next, seriatim, and a servomechanism for rotating said element through arcs proportional to the voltages derived from the taps on the transformer by the slider, said servomechanism including a feedback unit energized by said reference voltage, means for driving the feedback unit in accordance with the rotation of said element to produce a feedback voltage which is linearly related to the rotation of said element and which is equal to the reference voltage when the element has been rotated exactly 360 degrees, and a servoamplifier for comparing the voltage derived from said taps with the feedback voltage and for amplifying the difference, if any, between said voltages.

5. In a device for dividing any given dimension on a piece of work into any selected number of equal parts, the combination of a source of reference voltage, a first unit energized by said reference voltage for providing a first preselected voltage which is representative of the distance between a first datum point and one end of said dimension, a second unit energized by said reference voltage for providing a second preselected voltage which is representative of the distance between a second datum point and the other end of said dimension, a transformer having a winding with a plurality of equally spaced voltage taps thereon, switch means for selectively connecting said preselected voltages across a number of taps on the transformer winding equal to the number of parts selected, a slider movable from one tap to the next seriatim, and a servomechanism for moving the workpiece through distances proportional to the voltages derived from said units and from said taps by the slider, said servomechanism including a feedback unit energized from said source, means for driving the feedback unit in accordance with l i the movement of the workpiece to provide a feedback voltage which is linearly related to the movement of the workpiece and which is equal to the reference voltage when the workpiece moves from said first datum point to said second datum point.

6. In a device for dividing a linear function into a given number of equal parts, the combination of a transformer having a multisection tapped winding thereon, the taps in each section being spaced equal numbers of turns apart so as to provide equal voltages between taps and the number of turns between taps in the difierent sections being related in accordance with the radix of a selected number system, a set of selector switches for setting into the device the number of parts into which the function is to be divided, there being as many switches provided as there are numerical orders in the number representing the maximum capacity of the device, means for connecting a reference voltage across a number of turns on the transformer winding corresponding to a multiple of the number of parts into which the function is to be divided, said means including an automatic switching circuit for connecting across the reference voltage a number of turns in the highest order section of the transformer winding corresponding to the highest significant digit of the number set up on said switches and for connecting in series therewith appropriate numbers of turns in each of the descending orders of the transformer winding sections down to the section corresponding to the least significant digit of the number set up on said switches so as to energize a number of turns corresponding to a multiple of the number set up on the switches, a slider cooperating with the taps on each section of the transformer winding, an output circuit, and means for stepping said sliders from tap to tap in the energized sections of the transformer winding sections in a regular numerical progression to provide a voltage in the output circuit varying by increments equal to the voltage between taps in the lowest order active section of the transformer winding.

7. In a device for dividing a linear function into a given number of equal parts, the combination of a toroidal autotransformer having a three-section tapped winding thereon, the taps in each section being spaced equal numbers of turns apart so as to provide equal voltages between taps and the number of turns in the several sections being related in a to 1 ratio to provide a 10040-1 relation between the sections, means for connecting a reference voltage across a number of turns on the transformer winding corresponding to a multiple of the selected number of equal parts, said means including a stepping switch associated with each section of said transformer winding for connecting across the reference voltage a number of taps in the hundreds section equal to the value of the highest significant digit of the selected number of equal parts, a number of taps in the tens section equal to the value of the next highest significant digit, if any, and a number of taps in the unit section equal to the value of the least significant digit, if any, so as to energize a number of turns equal to a multiple of the selected number of equal parts, and a stepping switch associated with each section of said transformer winding for stepping from tap to tap in the energized sections of the transformer winding in a regular numerical progression to provide an output voltage varying by increments equal to the voltages between taps in the lowest order section of the transformer winding that is energized.

8. In a device for dividing a linear function into a selected number of equal parts, the combination of a transformer having a multisection tapped winding thereon, the taps in each section being spaced equal numbers of turns apart so as to provide equal voltages between taps and the number of turns between taps in the several sections being related in accordance with the radix of a selected number system, a plurality of selector switches settable to positions corresponding to the digits of the selected number of equal parts, and means for connecting a reference voltage across a number of turns on the transformer winding corresponding to a multiple of the selected number of equal parts, said means including a plurality of control relays, means for selectively energizing said relays in accordance with the location of the highest significant digit of the selected number of equal parts, and means controlled by said relays for transferring the setting of the selector switch containing the highest significant digit of the selected number to the highest order section of the transformer winding, the setting of the selector switch containing the next highest significant digit, if any, to the next highest order section, and so on, to thereby cause the reference voltage to be connected across the greatest possible number of turns of the transformer winding.

9. in a device for dividing an interval into a preselected number of equal parts, the combination of a transformer having a multisection tapped winding thereon, the taps in each section being spaced equal numbers of turns apart so as to provide equal voltages between taps and the number of turns between taps in the several sections being related in accordance with the radix of a selected number system, switch means for selectively connecting a reference voltage across a number of turns on the transformer winding corresponding to a multiple of the selected number of parts into which the interval is to be divided, a slider cooperating with the taps of each section of the transformer winding, an output circuit, and means to step said sliders from tap to tap in a regular numerical progression to provide a voltage in the output circuit varying by increments equal to the voltage between taps in the units order section of the transformer winding.

10. In a device for dividing an interval into a preselected number of equal parts, the combination of a transformer having a multisection tapped winding thereon, the taps in each section being spaced equal numbers of turns apart so as to provide equal voltages between taps and the number of turns between taps in the several sections being related in accordance with the radix of a selected number system, switch means for selectively connecting a reference voltage across a number of turns on the transformer winding corresponding to a multiple of the selected number of parts into which the interval is to be divided, an output circuit, a multibank stepping switch associated with each section of said transformer winding, each switch having one of its banks electrically connected to the taps of its associated section of the transformer winding with the slider of said one bank electrically connected to said output circuit, and a counting circuit for stepping said sliders from tap to tap in a regular numerical progression to provide a voltage in the output circuit varying by increments equal to the voltage between taps in the units order section of the transformer winding, said circuit including additional banks of the stepping switches so connected with one another as to provide a carry impulse from a lower order stepping switch to a higher order stepping switch each time the slider of the lower order stepping switch reaches home position.

11. In a device for dividing an interval into a preselected number of equal parts, the combination of a transformer having a multisection tapped winding thereon, the taps in each section being spaced equal numbers of turns apart so as to provide equal voltages between taps and the number of turns between taps in the several sections being related in accordance with the radix of a selected number system, a plurality of multibank selector switches for selectively connecting a reference voltage across a number of turns on the transformer winding corresponding to a multiple of the selected number of parts into which the interval is to be divided, an output circuit, a multibanlt stepping switch associated with each section of said transformer winding, each switch having one of its banks electrically connected to the taps of its associated section of the transformer winding and the slider of said one bank electrically connected to said output circuit, a counting circuit vfor stepping said sliders from tap to tap in a regular numerical progression to provide a voltage in theo utput circuit varying by increments equal to the voltage between taps in the units order section of the transformer winding, and means for preventing further stepping of said sliders when the voltage in the output circuit becomes equal to the reference voltage, said preventing means including banks of said stepping switches connected in circuit with banks of said selector switches, said circuit being completed when the settings of the stepping switches and selector switches coincide.

12. in a device for dividing the movement of an element through a predetermined distance into any selected number of equal parts, the combination of an autotransformer having a tapped winding thereon, said winding having a number of turns equal to a multiple of the maximum number of parts capable of being selected, switch means cooperating with the taps on said winding for selectively connecting a reference voltage across a number of turns equal to a multiple of the number of parts selected, means to derive a number of incremental voltages from the transformer equal to the number of parts selected, said means including a slider movable from one tap on the transformer winding to the next seriatim, and means for translating the voltages so derived into equal steps of movement of said element, said steps being proportional to the magnitude of the voltages derived from the taps by said slider.

References Cited in the file of this patent UNITED STATES PATENTS 2,654,999 Berge Oct. 13, 1953 2,715,703 Shuck Aug. 16, 1955 2,736,006 Langevin et a1. Feb. 21, 1956 2,775,754 Sink Dec. 25, 1956 2,826,726 Mitchell Mar. 11, 1958 2,833,979 Scott May 6, 1958 

5. IN A DEVICE FOR DIVIDING ANY GIVEN DIMENSION ON A PIECE OF WORK INTO ANY SELECTED NUMBER OF EQUAL PARTS, THE COMBINATION OF A SOURCE OF REFERENCE VOLTAGE, A FIRST UNIT ENERGIZED BY SAID REFERENCE VOLTAGE FOR PROVIDING A FIRST PERSELECTED VOLTAGE WHICH IS REPRESENTATIVE OF THE DISTANCE BETWEEN A FIRST DATUM POINT AND ONE END OF SAID DIMENSION, A SECOND UNIT ENERGIZED BY SAID REFERENCE VOLTAGE FOR PROVIDING A SECOND PRESELECTED VOLTAGE WHICH IS REPRESENTATIVE OF THE DISTANCE BETWEEN A SECOND DATUM POINT AND THE OTHER END OF SAID DIMENSION, A TRANSFORMER HAVING A WINDING WITH A PLURALITY OF EQUALLY SPACED VOLTAGE TAPS THEREON, SWITCH MEANS FOR SELECTIVELY CONNECTING SAID PRESELECTED VOLTAGES ACROSS A NUMBER OF TAPS ON THE TRANSFORMER WINDING EQUAL TO THE NUMBER OF PARTS SELECTED, A SLIDER MOVABLE FROM ONE TAP TO THE NEXT SERIATIM, AND A SERVOMECHANISM FOR MOVING THE WORKPIECE THROUGH DISTANCES PROPORTIONAL TO THE VOLTAGES DERIVED FROM SAID UNITS AND FROM SAID TAPS BY THE SLIDER, SAID SERVOMECHANISM INCLUDING A FEEDBACK UNIT ENERGIZED FROM SAID SOURCE, MEANS FOR DRIVING THE FEEDBACK UNIT IN ACCORDANCE WITH THE MOVEMENT OF THE WORKPIECE TO PROVIDE A FEEDBACK VOLTAGE WHICH IS LINEARLY RELATED TO THE MOVEMENT OF THE WORKPIECE AND WHICH IS EQUAL TO THE REFERENCE VOLTAGE WHEN THE WORKPIECE MOVES FROM SAID FIRST DATUM POINT TO SAID SECOND DATUM POINT. 